As hinted at by Colton Haynes, Hal Jordan MAY be appearing in season 2 of Arrow. Personally I doubt it will be as Green Lantern, but there's always the possibility. Given how much crap DC has put Hal through since the New 52 began, it'll be nice to see him get some respect elsewhere.

With Hal they could make some references to a mysterious green light appearing in Coast City. Like have Coast City in the show be kinda like another Roswell, with Ollie or someone else bringing up all the "supposed" alien stuff. The famed Green Light of Coast City being one of them