Leave No Trace Outfitters - Backpacking in California and the Sierra Nevada with guided tours, practicing leave no trace ethics. - http://www.leavenotrace.com/
Tahoe Mountain Milers - Running club. Monthly meetings. Site lists frequent club runs, local races. - http://tahoemtnmilers.org/
Williams Sports - All-seasons sports rentals, including equipment for skiing and snowboarding, paragliding, mountain biking. Jet skiis, power boats, party boats. Seven locations in South Lake Tahoe. - http://www.tahoesports.com/
DeCelle Memorial Lake Tahoe Relay - 72 mile, 7 person running relay around beautiful Lake Tahoe. Annually 2nd Sat. in June. - http://www.laketahoerelay.com