"I lift things up and put them down" is a video meme spreading across youtube, featuring a phrase from a recent Planet Fitness advertisement.

The ad features a Planet Fitness instructor showing a dim-witted bodybuilder around one of it's stores.
When questioned on his profession, the bodybuilder proclaims 'I lift things up and put them down.', and continues to do so when shown the various equipment available to gym members, until he is tricked into leaving (not without another 'I lift things up and put them down' of course).

Starting with a video of a a small boy repeating the phrase, numerous people recorded and posted their own repetitions of the phrase on youtube, and a few remixes.

The phrase it making it's way around the message boards, and there's even a website dedicated to the phrase: iliftthings.com

Original ad:

Oblagatory Sparta Mix:

Cute kid:

Some sort of animated cat:

Many more examples to be had, just search Youtube.