I’m not sure whether my jokes would cost $10 million or more, but assuming the OP just means “Come up with a really awesome practical joke and money is no object” and I don’t have to prove I can pull these off with $10 million or less:
1. The Great Penguin Transfer. I’d hire a big freighter and have it outfitted with appropriate compartments to comfortable house penguins for a long trip. I’d have it steam down to Antarctica, and we’d capture about 10,000 penguins. Then we’d steam to the Arctic and drop them off on whatever Godforsaken island in the Canadian Arctic archipelago would best mirror their habitat. Then I’d pay the crew to keep their yaps shut.
Then just wait a few months, or a few years, until scientists find the colony of penguins in the Arctic. They’d shit their pants.
**2. The Great Jeopardy! Shankfest. ** I’d bribe my way into Jeopardy!, be a perfectly normal contestant, until Double Jeopardy. Then I’d start ringing on on every second clue with answers that were most, shall we say, unusual.
Alex: Alright, State Capitals for $800… this state capital is French for “red stick.”
Me: (Buzz!) What is my throbbing member?
Alex: Um, no.
Some Other Jerk: (Buzz!) What is Baton Rouge?
Alex: Yes. Go ahead.
Some Other Jerk: I’ll take State Capitals for $1200.
Alex: This is the southernmost state capital.
Me: (Buzz!) What is a really soggy pair of panties? Yeah. Yeah. Yeah.
Alex: No…
Some Other Jerk: (Buzz!) Honolulu?
Alex: Umm… yeah… go ahead.
Some Other Jerk: Uh, let’s try Literature for $400.
Alex: This author’s only novel, written in 1960, was named the best American novel of the 20th century.
Me: (Buzz!) What is that hooker I left for dead last night in a motel I’d checked into under an assumed name?