You can give your character a giant dick that flops around, same goes for tits.
There is a car that sucks people up into a cannon and then launches them at people and building.
You can be a dude with tits and a British male voice. The same goes for a chick with a floppy cock and a Russian voice.
The dev team made an entire system devoted to nut shots, with each weapon getting a unique nutshot.
You can run around town with you giant floppy dick and rub up against people.
Instead of using a boring old Ak-47 to kill some luchadore themed gang members, you can use a missile that you control in first person.
The 2nd mission has you jumping out of a plane and then jumping out of it again:
Saints Row The Third - Freefalling Mission
One of the games melee weapons is a giant 3 foot long purple dildo bat and another is a set of giant fists called the apacofists that make people explode into mush upon being hit.
Also, you can be a furry.
Ooh ooh ohh, the melee system allows you to do a flying head kick to an old lady's face and then strike a pose.
Oh, and there happens to be hoverbikes and VTOLs.
If all that hasn't convinced you you need this game as well, the following image and gameplay video should:
Saints Row The Third - Gameplay Commentary
Also, here is a nice preview someone made at Destructoid that tells you what I just told you but better: http://www.destructoid.com/saints-row-the-third-is-the-definition-of-a-fun-game-209076.phtml
Another preview from Kotaku in poem form: http://kotaku.com/5831542/a-rip+roaring-rhyming-hands+on-with-saints-row-the-third