A personal favorite of mine is one I came up with on a whim for a dinner party... it's the one part people still talk about, and it was easy to throw together. It's a scoop of vanilla ice cream and a scoop of mango sorbet, topped with raspberry daiquiri coulis. You can do the coulis by whirling up some raspberries in the blender along with a little lime juice and a bit of sugar. Add rum to taste, and serve. Alternately, make the coulis without the rum, then at serving time, warm a tablespoon of rum with a lighter applied to the underside of a metal spoon, then light it and pour on to the dessert. For bonus points, drizzle it from about a foot over the table. Just don't do this while any linens are on the table.
Bananas Foster are a big hit every time I serve them .
Melt some brown sugar in butter in a sauce pan, add orange juice, zest of orange, cinnamon sticks, good dark rum and banana liqueur.
Brown the banans in butter and serve with Hagen Daz Vanilla ice cream and lots of sauce.
P.S. You can do the flambe routine too with heated booze but be careful if you haven't done it before.