So, I'll be making my first visit to Las Vegas for four days starting this Sunday. I won't have access to a rental car, so I'll have to use cabs or whatever to get around. I also have a few obligations and things I'll have to be doing while in Vegas. That said, I anticipate I'll have some good free time. Since I've never been to Vegas and haven't done any research about it, does anyone have any advice for things I should try to do or see?

We're staying in the MGM Grand and thats about all I know. This isn't a trip with a wife or girlfriend so nothing romantic or date oriented required.