Seeking info for dumb tourists

[tiggymalvern]

I'm going to be in Vegas for four days in late April, of which two half days will be taken up by the mundane work-related reasons for being there. So, all you well-travelled and tasteful people who inhabit my f-list - what's good to see that isn't Vegas? I'm thinking day trips out here, deserts and canyons and dramatic scenery - we'll be renting a car for the duration to get out of the city. Pour forth your knowledge and opinions upon me!

EDIT: Googling is suggesting the Valley of Fire State Park and Red Rock Canyon might be good places. Anyone been to the Hoover Dam? Is that worth a trip?