Not only can you learn a lot just by watching, as Yogi Berra once said, but it's often easy on the pockets.

* This Friday at 7:30, the Arlington Chess club sponsors a chess exhibition in which international master and world-ranked chess player Eugene Meyer of Northern Virginia will offer his commentary on the contemporary chess scene and then play 30 challengers simultaneously. It's all free, unless you want to play. Then, you have to be among the first 30 to sign up and pay $10. The event takes place at the Central United Methodist Church, 4201 N. Fairfax Drive, Arlington. The church is directly across from the Ballston Metro station on the Orange Line. For more information, call 534-6232 after 5.

* Snow or no, the renegade boys (and girls) of summer will be out on four diamonds in a two-day Chili Softball tournament at Lee District Park this weekend. This year, 64 slow pitch teams are entered, hoping to play in snow so they'll have a better excuse to use orange softballs and warm themselves by eating chili between games. The action's on Saturday from 8 until dark; Sunday, 8 to 4. The park is at 6601 Telegraph Road, (take Beltway exit 2-S 21/2 miles to park entrance on the left. Call 922-9841.