I enjoyed Blue Man Group quite a bit, my wife thought it was ok.
If you want something a bit more risque, a buddy of mine swears by Zumanity at Luxor.
Casa Fuente is must, as already noted.
There are a number of good sports books out there, my favorite is probably Mandalay... Wynn is good too but I don't like gambling there. CA just had an article about the new electronic sports gaming options at a couple of hotels but I can't remember which ones.
Craft Steak (MGM) is a great restaurant to check out - a variation of the Craft restaurants. I think they have a whisky pairing meal option as well.
Actually, if you are in to food... I mean really into food... MGM Grand has one of the only 3 Michelin star restaurants in the US. This is one of those places where they bring out a platter just for the appetizer bread. They have over 30 types of appetizer bread.
If you are taking kids, the shark reef at Mandalay was cool (it was ok, but my nephew really liked it). Same with the dolphin exhibit at Mirage.
I would check ahead to see what special shows may be happening, especially at the House of Blues in Mandalay (this is a hot/cold spot), and at Caesars (i.e. Seinfeld plays there a lot).
If you like Pete Rose, he is ALMOST ALWAYS signing autographs in the forum shops just down from Casa Fuente. Probably paying off a debt to the casino... (kidding, kidding!)
Mandalay has some decent concerts too so I'd check ahead there.
If you like Minor League baseball, LV has a team... the 51s... there are games in June, of course.
Deuling Pianos in the New York New York are a good time (assuming they still have it, been about a year or so I think since I went to that).
Bellagio buffet is good (Wynn's is awesome too but I like Bellagio more, same for Rio), Caesars has a nice coffee shop for breakfast.
If I can think of more I'll post... it has been a while since I've really hung out on the strip - we usually stay out at Lake Las Vegas or at Green Valley Ranch when we go anymore.