Clark County Wetlands Park has guided walks, talks, and programs every month. Some require advance registration. Quite a few are for kids, such as Nature Tales, which includes a story and a craft. Guided walks are for ages 10 and over. Also, art classes for all ages.
The Southern Nevada Rock Art Association meets on the fourth Monday of every month, starting at 6:30 p.m., in the REI store in Boca Park. Admission is free and anyone interested in rock art is invited to attend. There's usually a program on rock art and/or archeology, most often local or regional.
Viva Las Vegas! Bike MS: Las Vegas returns for its fourth year October 27, with three routes: 30, 50, or 100 miles across the Southern Nevada landscape. The rides atrat and end at the Clark County Amphitheatre. There's a $200 fundraising minimum.