Whenever I'm in Vegas I take a break from the strip and head here to gear up for some healthy recreation in the beautiful surrounding red-rock mountains.
About 10 mi off the strip you'll find the a huge selection of bikes and accessories to outfit any 2 wheeled (human powered) adventure. The shop carries top end products at fair prices. The staff is friendly and helpful. They rent road and mountain bikes (Specialized and Ellsworth) at slightly high prices but the quality is excellent. If you plan to rent you better reserve in advance as they often sell out for the day.
Its also home base for Escape Adventures, offering premiere day and multi-day trips around the south west. The guides are awesome riders who are more than willing to share their knowledge of riding and the local terrain.