There are actual autonomous robot competitions. They don't tend to be as adrenaline-filled as the battlebots, they really don't make good TV, but they're fun. Some have quite low barriers to entry. If you want to dip your toe in you can put together a mini-sumo or maze-running entrant without a ton of time/materials investment.
I am actually looking forward to robot competitions, even AI Quake/StarCraft battles.
The closest thing we have right now is radio controlled battlecars banging each other. Not terribly exciting after the first few minutes