we haven't got any toys or mobiles in/near his cot (partly cos I just haven't gotten around to buying a mobile)... but we recently rearranged the room and there's more on the walls above his new cot location, but doesn't seem to have fussed him too much.

So saying, when it was soooo hot here yesterday I put him on the big mummy & daddy bed (with some barriers to stop him rolling) and let him watch the ceiling fan. It worked wonders (as well as cooling him down) and he went off to sleep...