I agree with the WOZ monkey lock, it's cool.
I would also like to mention TSPP for its use of locks. I mean, it has the couch lock, which is pretty cool.
But during alien invasion, this game becomes a frantic rush of ball locking awesomeness.
The TV, garage, Itchy and scratchy hole, and Otto shot all become locks, in addition to the couch.
It's a brilliant mode, and I can say that I've never wanted to lock balls in any other game as much as I have during that mode.
I guess this post is more about the mode than the locks themselves but still wanted to mention it because it's a blast.