Las Vegas - Discount show tickets anywhere?

Does anybody know if there is any place that sells same day or rush tickets for shows at a discount? Obviously the popular ones (i.e. Celine Dion) might not have any available, but I think some of the other ones (i.e. Mamma Mia, Penn & Teller) might have tickets on weekdays of less busy weeks. I guess I'm looking for something similar to the TKTS offices in New York City.

Nothing for Penn & Teller, but Mama Mia is 1/2 price at Goldstar Events (http://www.goldstarevents.com/)

There are 1/2 price same day outlets on the strip, Tickets2Nite & Tix4Tonight, post available shows around 11:30 and open at noon. Usually your "B" shows and some attractions, maybe a discount on "A" Cirque and the like, but that's spotty if at all.

Might also want to check out this locals page.

Sparky's Las Vegas Coupons (http://members.cox.net/sparky-dog8/Coupons.htm)

Has some 2 for 1's, which saves you the trouble of going to the outlets & no fees, a VIP pass and $1 off at Tix4Tonight, club passes and guestlists, and bunches more. Best list of links to free online printable stuff I've found anywhere and it's saved me a ton of money and time.

Also some interesting Vegas info found on the More Vegas page, and I see they added a link to it on the top of the coupon page. Travel, entertainers sites, and some things around Vegas I didn't know where there.

If you like dogs, check out the videos on the home page. This site is actually a personal page for their dog that swims underwater!

Nothing for Penn & Teller, but Mama Mia is 1/2 price at Goldstar Events (http://www.goldstarevents.com/)

I used Goldstar for Mamma Mia this past weekend. Ticketmaster wanted to give me awful seats. I figured buying through Goldstar and not knowing what I'd get until I showed up at will call couldn't be any worse, and it wasn't. I ended up with 11th row center. ^ Goldstar.