I think one of the best parts about being a parent is discovering the many different ways you can make your children laugh. Tickling is very big in our house. My children have inherited my husband's hyper sensitive tickle genes. Evan loves to be tickled and will actually place my hand on his tummy when he wants to be tickled.
There are other less obvious laughter inducing things that get bigger laughs than mere tickling. A dinner time favorite is to have me take my glasses off and make funny faces at the boys. I think it is the combination of me being silly and changing the look of my face by taking off my glasses. The hand monster is also a huge hit, especially with Harry. The hand monster will sneak out from under blankets to prey on unsuspecting feet. It will also walk along dinner tables and try and gobble hands.
A game I call fake sneeze is the bath time favorite although Evan is taking it out into public. Fake sneeze involves one of the boys placing a bath toy onto the side of the bath tub. Mommy then fake sneezes and knocks it back into the bath tub. I have to keep control of this game since Harry has been known to laugh so hard he falls over and risks drowning. The other day I saw Evan throw a toy into the air and then fake sneeze. That was his toddler version of the game. He is also just randomly sneezes and laughs.
The number one thing that is guaranteed to get the kids laughing so hard they can barely stand is called "Daddy throws the yarn ball up the stairs and Mommy throws it back down". DTTYBUTSAMTIBD was discovered quite by accident. I was cleaning with my little helper Harry upstairs. I threw the yarn ball down the stairs because I had been intending on using it to knit with. Evan happened to see it go down and started laughing up a storm. He then tried in his toddler way to throw it back up the stairs. Luckily his efforts were quickly augmented by daddy who had a much stronger arm and could get it to the top of the stairs. Of course I had to throw it back down just for fun. We did this for as long as we could stand the mindless activity and the entire time the kids were laughing hard. Now and then on grumpy days we give that silly yarn ball a toss and everyone feels a lot better.