Here's some ideas I was kicking around while I thought nastolgically about 1080 on N64:
First of all a realistic and believable mountain that you can snowboard every single inch of, the areas between runs, runs, ect. from top to bottom. There will be lifts to get up higher (a sequence which is obviously masking the laoding times and is therefor like ten seconds or less). Pressing start will bring up a map modeled after the ones available at most snowboard resorts so you can see what runs you are above, below ect. and what lifts take you where.
Then I thought "Ooh...make it in depth" like that cabin interface? That was cool--make it even better, have a strory. Have it a guy or girl move into a shanty by the resort (you should be free to customise the character all you want as far as sex, height, weight, color and a limited selection of clothes) and you have a pretty piss-poor snowboard, boots, bindings, ect. along with ugly out of fashion clothes. You have to earn money by doing things on the slopes and beating people, which in turn unlocks them, and as you do this you up your stats.
Has anybody ever seen the movie "Out Cold"? It's on Comedy Central a lot--if you've seen it, you'll know the sort of thing I'm thinking of
Another thing is once you unlock the other players you can play through stories with them to upgrade thier stats as well
And then the obvious; online play, but I don't think I need to explain this one.