Summer of Sonic, in the nuttiest of shells, is a Sonic the Hedgehog fan convention that’s being backed by Sega Europe. It’s being held 9th August at the Covent Garden Dragon Hall Trust in Central London and is free to attend. Blue hair dye is optional.
As well as some poor sap dressed up as Sonic, there will also be the chance to play Sonic games of yore (including a Sonic 2 contest with prizes), see some rare Sonic merchandise, read issues of various Sonic comics and play a new Sonic game – presumably Sonic Unleashed. Or maybe Bioware’s Sonic Chronicles.
The dedicated website can be found here. Maybe you could get them to run a Sonic 3 contest instead. Sonic 2’s two-player mode was a glitchy mess. Great music though.