Ok, to you young ones - even though I am 36 years young - for Valentine's Day you could do this:
1) make cupcakes and decorate them in colors of red/pink/white (cinnamon candies are good decorations too)
2) download a favorite tune of yours - or go out there and get a CD of your chosing;
3) make dinner for your parent(s);
4) make cut out hearts and decorate them and you can either put them up in your room and/or give them away to a loved one (like your grandparent(s), parent(s), brother/sister, etc.);
5) or get those paper doillies (you can get these and craft supplies at any local ($) Dollar Store) and decorate them with glitter, etc.;
6) send your self a valentine gram or something like that at school (a friend of mine sent herself balloons - yeah, that was an attention grabber);
7) take a nice bath and relax;
Well, these are some of the things I did when I was younger (and still do to this day with my kids).
I hope I helped in some little way...enjoy!