I am currently hooked on Guitar Hero. Just learned to activate Star Power and am making great progress on the Medium level. I aim to play my 70s/80s repertoire at the Toxic festival tonight and then spend my hard earned rock cash in the Guitar Hero shop. I'm saving up for the Grim Reaper guitarist...he has long fingers and looks as though he can reach difficult chords.:-)
If this proves too hard for you then why not buy a guitar that you can wear? Some textile students in Australia have devised a t-shirt that allows you to play air guitar. If you make a strumming movement with the left hand then you are activating the strings of your air guitar and moving the left hand up and down the virtual fret board changes the chords.
Alas, frantic finger movements do not yet facilitate solos in the style of Hendrix, Page or my favourite Frehley!