Birthdays, for a little Cuban American conga drum player, always held a few surprises. One year Superman flew in over the kitchen counter to land amidst a crowd of the 5-year-old's cheering classmates -- while a certain redheaded imposter, cape and all, stood clinging to a rusty drainpipe on the building's ledge.

Another year, birthday greetins came from a party going on some 4,000 miles away. It seems that his homesick mother, in Florence at the time, had given a chocolate bar to a little Italian boy who claimed to have the same birthday as her son. Before long, a whole procession of wide-eyed tots started knocking at the door, insisting that "Today, she's-a my birthday, too!"

But today's birthday probably holds the biggest surprise of all -- for the rest of us, at least. Hard as it is to believe, television's First Baby, Little Ricky Ricardo, turns 30 years old.

Many of you undoubtedly recall that fateful night -- Monday, Jan. 19, 1953, at 9 o'clock -- when an estimated 44 million Americans tuned in the most popular "I Love Lucy" episode of all time. The high point came as Ricky raced into the hospital from the Tropicana Club -- decked out in a witch doctor costume -- to welcom his baby boy into the world.

Lucille Ball actually was due to have her and Desi Arnaz's second child by caesarian section that day. Americans had little doubt that the two newborns would be the same sex. After all, weren't the Arnazes really the Ricardos with a different name?

That is a delusion I wholeheartedly embrace. For me, Lucy, Desi, William Frawley and Vivian Vance ceased to be anything but the Ricardos and those lovable Mertzes after April 1, 1960, the date of the last "Lucille Ball-Desi Arnaz Show" that teamed the quartet. Little Ricky, to my mind, always will be his daddy's "little amigo." Never mind that I recently spoke with Keith Thibodeaux (TV name, Richard Keith), the once diminutive drummer who played the part of Little Ricky, and learned not only that he's really 32 years old, but that he has a Louisiana accent. (Two sets of twins played Little Ricky until Thibodeaux took over the role at age 5.)

For most of my 27 years in front of the tube, I've been a closet "I Love Lucy" addict -- one who would stay from grade school to catch an almost-forgotten episode. One who, even today, sets the alarm clock on her days off to the 9 o'clock Channel 5 reruns.

Few people were privy to this all-consuming passion. Only my mother and husband have ever heard me recite whole passages of dialogue in sync with the characters, or listened to me sing the words to the "I Love Lucy" theme song. I never dared reveal some of the things I remembered, like the address of the Ricardos' Manhattan apartment (623 East 68th St.), Fred Mertz's home town (Steubenville, Ohio), or the name of Little Ricky's dog (Fred). Some things are just too embarrassing to admit.

Actually, I didn't realize how much worthless information I had acumulated until two months ago, when a know-it-all colleague challenged me to a television trivia quiz. Suddenly my pride was at stake.

We agreed to a Lucy contest. My colleague, as usual, went first:

"Who played Fred Mertz?" he asked, an insolent grin on his face.

"Oh, come on," I cried. "Ask me something difficult."

"No, no! You have to answer."

"Oh, all right. William Frawley," I said. "Now my turn. When did William Frawley die?" (March 3, 1966).

His mouth dropped in an uncharacteristic display of amazement.

Soon afterward I learned that there are people out there who not only care about such information ... They're willing to pay for it. My colleague (who, much as I hate to admit it, remembered Ethel's father's name) shared with me two invaluable reference works I didn't even know existed: Lucy & Ricky & Fred & Ethel, The Story of "I Love Lucy" (1977 Popular Library paperback, $2.50), and The "I Love Lucy" Quiz Book. (1981, A.S. Barnes, $5.95), both by TV triviaphile Bart Andrews.

In the first book, Andrews reveals in exhaustive and often repetitive detail how the show came on and stayed on the air from 1951 to 1957. You learn such things as how the series was named. Lucy didn't want to upstage Desi in the title; the network didn't even want the hot-headed Cuban in the show. Finally Lucy agreed to the title when it was explained that the "I" referred to her husband.

The "I Love Lucy" Quiz Book asks a thousand probing questions about the 179 episodes. Lke what kind of soup Lucy served Mr. Littlefield (Gale Gordon), Ricky's first boss (it was split pea), and the gift that Ethel really wanted for her birthday (a toaster).

"I Love Lucy" is a treasure trove for trivia lovers, since the writers couldn't keep their facts straight from one show to the next. At various times they gave Ethel's middle name as Roberta, Louise and May. Worse still was their confusion over Lucy's saxophone repertoire. Surely everyone remembers from the early days that Lucy could only bellow a few pitiful notes of "Glow Worm." But by the end of the series her lone number was a listless "Sweet Sue."

(Buyers of this book beware; even the estimable Bart Andrews can make a mistake. When Lucy was trying to get Ricky a raise, Andrews claims she told Mr. Littlefield that Ricky had 12 other job offers. Actually Lucy said four at the same time that Ricky blurted out 12. Explained Ricky, "I got eight more this morning!")

Aspecial Club has been formed for Lucy-lovers like me. (Some would suggest a home.) It's "We Love Lucy," the International Lucille Ball Fan Club. Yearly dues of $10 entitle you to a "We Love Lucy" lapel pin, an official membership card, and periodic issues of the club newsletter, Celebrating Lucy. For membership information, write Tom Watson at Box 480216, Los Angeles 90048.

For an idea of the club's popularity, you can try calling any of the Tom Watsons listed in the L.A. phone book. Recently I asked the wrong Tom Watson, rather sheepishly, whether he was the "We Love Lucy" president.

"Where are you calling from?" he asked in reply. I told him, punctuating my response with a why.

"Because I get calls from people all over the country," he said, "and I get kind of a kick out of keeping track."