Unless you're playing limits where you feel you would take a serious hit if you lost, I'd use this as a possibility to work on your reads. First off, this is a game of friends. Chances are you're just as excited (if not more) to just get together and have fun than you are about winning money. Don't forget to have fun. So, play in a way that's fun for you - folding 40 hands preflop because it's the right thing to do to maximize winnings might be counterproductive for the fun-factor of it, although I in no way recommend playing "poorly", I still suggest you play in a way that you find fun. If you enjoy being tight, then by all means, go tight.
But, from your post I gather you also don't want to miss out on an opportunity to improve your game, which is great and shows a healthy attitude towards poker. So, without ruining the "fun" of the game, focus more on the people than on the numbers. Be more concerned with the players instead of your cards and the pot odds
. Three of them you apparently know well, and three of them may be strangers. See if you can figure out, in detail, how they like to play different hands. Even if you fold pre-flop, follow the rest of the hand, predict the hands they hold, and finetune if you get it wrong.
This way, you're still actively engaged in having your friends over, while working on an important poker skill, and not locking yourself into your own cards or odds or probabilities.
Of course, this may not suit you at all, but advice requested and advice given.