Taking a Vegetarian to Vegas

I'm bringing my younger brother to vegas for his 21st birthday. I usually frequent seafood places and steakhouses on vegas trips, but my brother is a vegetarian.

I'm looking for suggestions of places to grab lunches and especially dinners. I've done some searches, but related threads tend to focus on fine dining.

Relevant factors:
-- We're staying at Bellagio and don't mind venturing anywhere on the strip, but don't want to go beyond that.
-- He likes Italian, but is willing to try other things, provided no meat of course.
-- I'm not too concerned about prices, but he's definitely not a foodie and wouldn't likely appreciate high end places.
-- Places I've considered so far are Maggiano's at the Fashion Show Mall, and that's about it.
-- While good food is sought, I'm equally concerned with him having a great time, so fun, unique places and people watching are desirable.

Thanks in advance.

moosehog in Las Vegas