amas

Fun was definitely on the menu for the '2011 American Music Awards' (Sun., 8PM ET on ABC). The night was absolutely packed with memorable performances and surprise guest stars. Fighting Gravity went unannounced, but certainly helped make the debut of will.i.am's collaboration with Jennifer Lopez on 'T.H.E. (The Hardest Ever)' one of the most memorable of the night.

Other surprise appearances included a couple of guests who crashed the party at the end of the night with LMFAO performing their two hits. First, Justin Bieber broke out his dance moves on 'Party Rock Anthem,' and then David Hasselhoff joined the boys and Quest Crew to shake his moneymaker on 'Sexy and I Know It.'

There was a bit of a time-warp on tonight's '2010 AMAs' (Sun., 8PM ET on ABC). In fact, if you fell asleep in front of the TV, then suddenly woke up, you could have been forgiven for thinking that you were dreaming ... that you were back in the year 1996 -- or even 1986.

The Backstreet Boys and New Kids on the Block appeared on tonight's American Music Awards. Yes, the two boy bands are "back." And though the Backstreet Boys never really left us -- continuing their career to the present day -- New Kids on the Block famously tried to re-brand themselves as "NKOTB," then gave up and broke up the band in 1995.

Now, the two former teeny-bopper groups are touring together, using the semi-unwieldy name of "NKOTBSB." Tonight's AMAs represented their coming-out party of sorts. Though the "Boys" were popular in the mid-'90s, and the "Kids" were all the rage in the mid-'80s, it's been a long time since they've had mainstream success.

I had the American Music Awards on last night in the background, and for the most part it looked like a pretty standard awards show: People wore pretty dresses, played pianos suspended by wires, wore more makeup than their wives (I'm looking at you, Keith Urban), and simulated oral sex. Wait-- what?

Yeah, so for once, Lady Gaga's performance, which involved smashing a plate-glass window and setting a piano on fire wasn't the most interesting performance of the night. Instead, everyone is talking about two people: Jennifer Lopez and Adam Lambert. Lopez's unfortunate fall during her performance of "Louboutins" probably mortified her, but it wasn't the most awkward thing to happen during the ceremony. That distinction goes to American Idol runner-up Adam Lambert's decidedly non-family-friendly performance.

You can check out both videos after the jump.