Just in case you are actually serious.
Carp will feed on the surface but usually only if there is a ton of food available, so if a guy were to chum them with bread (illegal in or I think) you could probably get them on a bread fly. They will come to the surface for natural food sources like cottonwood seeds, large bug hatches or berries falling in the water as well. But, when surface feeding they are pretty obvious and in my experience they rarely do it unless there is a lot of food on the surface. Like most fish, they eat the bulk of their diet subsurface.
Look for feeding fish that are tailing (head down and tail up) and then put the fly right on them. They have crappy eyesight and feed by scent and feel so you really have to feed them an artificial, non scented fly.
As to what fly, anything that looks like food they are used to seeing. Due to their eyesight, you don't need to be fancy and general looking stuff is all I use. As mentioned, San Juan worms are great. I use a basic green nymph with hackle in a size 12 a lot. Other flies worth trying would be rubber legged hares ears, wooley buggers and the carp carrot (orange fly with dumbbell eyes). I fish mostly sizes 10-12 so they don't make much splash. Get the fly to sink and hit the bottom within the carps cone of vision and if they see and like it, they will usually mosey over and pick it up. Don't expect a big charge or firm take.
Good luck, hope this helps.
Found a pic of the green fly that I fish a lot. They ate the he'll out of this last season...