This week saw a variety of viral videos, from a nostalgic flip book to celebrity cameo appearances ... even ninja references. (hi-yah!)

Leading the bunch is the 'Late Night' video of Jimmy Fallon singing Miley Cyrus' 'Party in the USA,' using a distinct, perfected impersonation. We realize nothing could beat the all-too-catchy original, but this version is pretty good competition.

See what other viral videos we picked as our favorites this week. (Naturally, my favorite is the Puppy to Adult one...)

Neil Young with Crosby and Nash: Party in the USA


Flipbook Animation: Sonic the Hedgehog

Greatest Homeless Man Sign

Cat Mom Hugs Baby Kitten

Super Beagle

Ninja Warrior Birthday Party!

Time Lapse: Puppy to Adult in 40 seconds

Chill Out, TNT Camera Guy