I think eel sounds pretty exotic, but an eel and cucumber or eel and avocado roll is fairly tame on the tongue.
I also think that with some of the "spicy" rolls, you can't really tell what you're eating anyway. Spicy shrimp is probably not very intimidating.
If you want really tame, a California roll is about as pedestrian as it gets. Imitation crab (it's really fish), so there's nothing "dangerous" about it. And if you're a sushi virgin, it lets you start slow and maybe figure out the condiments (e.g. wasabi, soy sauce, and ginger). And if you really want baby steps, you can go from California roll to California roll rolled in roe.
I'd throw soft-shell crab rolls in there for a sushi-wary person. It's crab, and it's cooked.
Oh, and those tempura-battered rolls? Those are cooked and fried, usually with salmon inside. That's pretty tame, too.


