It's called #handstandsforpancan.
David stopped by the Preston and Steve Show at WMMR to talk about the handstand challenge that raises money to fight pancreatic cancer.
He did one himself (with the help of the P&S intern).
If you want to take part in the challenge, you take a photo of yourself performing a handstand and post it on social media with #handstandsforpancan, tag some friends, and give a donation.
'Jeopardy!' host Alex Trebek is currently battling the disease - which is very hard to detect and often found after it's too far advanced.