It's On!

Some alternatives, from Solipsist and family, to the by-now-cliched, "It's on like Donkey Kong!":


It's on like Pong!
It's on like a bong! (For all the stoners out there. And also for you guys: "It's on like Ding-Dongs!")
It's on like Pokemon!
It's on like Charon! (You know, the ferry guy. . . .)
It's on like mah-jongg!
It's on like Cinnabon!
It's on like Dom Perignon!
It's on like Sean John!
It's on like the Boston Marathon!
It's on like "The Wrath of Khan"!
(Or, for that matter, "It's on like Ricardo Montalban!")
It's on like Jean Valjean! (For you literary types)
It's on like Goldie Hawn!
It's on like a chess pawn!
It's on like Papa John's!
It's on like M. Night Shyamalan!

Or, for a little more variation:

On it like Rihanna!
On it like a bonnet! (Digression: We've actually heard someone use this one; not very intimidating. EOD)
On it like a sonnet! (14 lines of iambic pain!) (Digression: Sounds like something Sleep-Talkin' Man would come up with)
On it like Madonna!
On it like a piranha!
On it like Pocahontas!
On it like Kurt Vonnegut!
On it like Mohammad!

(WOS: "I'm on it like a donut! Ohhhh, that wasn't good. . . .")