I was thinking about this a while ago.

Ideally, I'd like to be buried inside a small pyramid in Antarctica, with walls covered in murals depicting me fighting valiantly against robotic vikings. My corpse would be frozen with crossed arms holding a Nintendo, packed inside a reduced-scale replica of a space shuttle. Once everything was in place, the pyramid would be buried deep under the snow, and hopefully all records of it would be destroyed.

Basically I'd like to create something silly enough that whoever discovered it a few hundred or so years later would never be believed.

We gave my grandfather a similar treatment. He asked to be cremated and the crematorium gave us this small container that reminded me of a Nestle Quik container with the metal lid/stopper that you had to pop out to get to the good stuff. It was going to be a few days before we were scheduled to pitch the old coot off his favorite covered bridge so we decided to take Gramps off to Aunt Betsy's. Aunt Betsy has a pool!!!! Gramps isn't exactly waterproof. Nothing duct tape can't fix! While we are at it let's make Gramps a raft since no one wants to pick the bugger up off the bottom of the pool all day and duct tape is only good to a certain point. Uncle Bob's Styrofoam cooler will work for that. Still a possibility of capsizing. Grab the kitchen knife and cut a hole in the bottom, more duct tape to strap the old fart in. While, Pap floats around the pool polish off a few beers. Ooo, the waterslide looks like fun! I bet Grandpa wants to go down the waterslide too. He does! It was the best afternoon I had with my grandfather.