If he is as shy as you say he is he probablly will never tell you if he does like you. I know you don't want to tell him you like him but just do it he probablly like you too!
Simply say "I like you." or try flirting. Main thing is to be yourself. No guy likes a kissup.
I think it'll be really hard to avoid asking him without making it obvious. It needs to be made obvious.
You could go the blatant route and dress like Christina Aguilera in the Lady Marmalade video and gyrate up and down in his face, but I guess you're looking for subtlety.
Ask him to go for a drink with you, one on one, or to the cinema if you're looking to avoid alcohol. Although sometimes alcohol helps to broach this topic, so long as you're not so cranked you projectile vomit all over his jacket.
But sometimes honesty is the way forward. What's so wrong with just saying simply and matter of faculty: "I like you, I'd like to do something nice with you tonight, and we'll see what happens. We'll either start dating or be better friends, but either way we'll have fun. I'm not taking no for an answer, you're picking me up at eight."
Get one of your mates to ask him for you tell her/him to say that you really like him good luck