* TAKE A LOOK: Sometimes the hardest thing to see, and this is especially true for Washington area paddlers, is the adventure that awaits right outside your door. You can spend hours dreaming up trips to France or New Zealand or Chile, but the Potomac River, though it has its fair share of problems, also offers within a short stretch some of the most varied and difficult whitewater.

This was brought home Friday when I sat on a rock outcrop amid Great Falls, the first time I'd been over there. Right below, the water pounded down a tight chute, swirled over a pinning rock and soon dropped out of sight. This adventure would have to wait for another day, when my skills were commensurate with the challenge.

Anyway, you can find plenty to get into on the river, especially if you take part in a Discover the Potomac Paddle Trip, an ongoing series put together by the Potomac Conservancy and Potomac Paddlesports. The next trip, which starts from Pennyfield Lock on the C&O Canal National Historical Park in Potomac, will run from 8:45 a.m. to 1 p.m. on Aug. 28. There also will be a "Full Moon/Nights Sounds Kayak Paddle" from 7 p.m. to 11 p.m. on Aug. 29-31. For more information, visit www.potomac.org. . . .

On Aug. 29, REI's College Park store will host a full-day course at Lake Audubon in Reston focusing on refining the skills needed to become a competent sea kayaker. Those who take part should have experience with the basics -- strokes, boat balance, edging, etc. Gear will be provided. For more information, visit www.rei.com.

* HOOFING IT: The Potomac Appalachian Trail Club is hosting a number of trips this week.

On Tuesday there will be a two-mile family hike around Lake Royal in Fairfax (contact Lauren Lang at at94L@netzero.net). Also on Tuesday is a trek for vigorous hikers in the North District of Shenandoah National Park in Virginia. You'll go about 17 miles. Trip leader is Chris Nolen (chrishiker@erols.com). And on Saturday another group will go the North District of Shenandoah, as part of the waterfall and wildflower series, for a 14-mile hike. Contact Jack Thorsen (thorsen4@juno.com) or William Needham (Needham82@aol.com). For more information, visit www.patc.net.

* CLUED IN: The Fairfax Audubon Society will offer a 10-week course on the ecology of the Chesapeake Bay starting Sept. 11 at Flint Hill School in Oakton. Topics to be covered include ecosystem energy flow, estuarine ecology and wetlands. There also will be field trips. Moreover, the Fairfax Audubon Society will offer classes focusing on mid-Atlantic forests, fall wildflowers, waterfowl, birding skills and digital photography. For more information, visit www.fairfaxaudubon.org.

-- John Mullen

mullenj@washpost.com