In case you are looking for some Vegas shows to see and don't want to pay the crazy regular prices, this is a great option to check out for same day tickets. They have different shows listed everyday at discounted prices depending on the demand for each show. Don't expect every show to be there and there's probably better discounts during the weekdays when less people are in town. First come, first serve.
The place is located in the Showcase Mall next to the MGM at the gigantic Coca-cola bottle you can see from the Strip. You can also call the number every morning to find out what might be available and buy via phone. Only downside is that they only have 1 physical location (unlike Tix4Tonight) if you don't prefer to buy via phone.
One minor inconvenience to note: They typically give you a ticket voucher for the show that you must present at the specific event box office AT LATEST 1 hr before the event. This can cut into your time since you have to show up at least 1 hr before the event.
Hint: If you pick up one of those Vegas magazines, there is an additional $2 off coupon per ticket (up to 4 tix I believe) for this place and you can save more. They will even take competitor's coupons (e.g. Tix4Tonight). Also if you buy from here once, they give you a VIP pass so you can skip the regular lines the next time you come. Can save a ton of time and sweat if the regular line is a long line.
Bottom line: If you are looking for some discounted shows to fill in the gaps between your Vegas gambling and partying, this and Tix4Tonight are definitely great options to check out.