Entourage

From TeeVeePedia, the Internet TV Encyclopedia.

Entourage is an HBO comedy about up-and-coming superhero Aquaman (Adrian Grenier) and his friends/hangers-on: his best friend/manager Erik (Kevin Connolly), his has-been older brother Johnny (Kevin Dillon), his talking giant turtle (Jerry Ferrara), and his agent Jeremy Piven.

The original version of the show, simply titled Aquaman, was pitched to The CW, but was rejected, only to end up becoming a hit on the Internet.