Go Seth!

Two days after wrapping his inaugural week as the host of "Late Night," Seth Meyers sweated it out for a cause, pariticipating Sunday in the charity indoor cycling event Cycle for Suvival, which raises funds for rare cancer research.

Meyers and wife Alexi Ashe both rode at Equinox Rockefeller Center, where Meyers was "full of energy," a witness told us.

In his fourth year participating, the 40-year-old funnyman raised more than $12,600 -- 100% of funds raised go to Memorial Sloan Kettering Cancer Center.

Meyers attended Northwestern University with Cycle for Survival co-founder David Linn, whose wife, Cycle co-founder Jennifer Goodman Linn, died of cancer in 2011.