Video games would only be appropriate if this is a gift giving program that takes requests from families / children. Otherwise, the people who organize who gets what don't know what kids have a specific game system. The same type of situation holds true for clothing. Unless families/children are able to request specific sizes or items, the program cannot give these gifts.
Generic "safe" gifts would include things like hats & scarves since these are one size fits all. Most girls of teenage years could wear a regular woman's size glove (medium) and most boys in the teen years would take either a medium or large glove -- hard to know, really. Mine wears large because he has big hands.
Trendy hats & scarves are nice gifts. If the program DOES have clothing requests, then trendy zip up hoodies can be nice gifts (unless you are in an area prone to gang activity, in which case you may wish to avoid giving hoodies...)
There are some pretty inexpensive basic mp3 players now. These are decent gifts. Digital cameras are nice. You don't have to have a computer in order to use these anymore, so long as you get one that can be charged off the computer. Some are quite inexpensive now, too. Remember, you can print pictures by taking the memory card in to
Walmart. This type of thing would be nice for a teen.
Perfumes and colognes -- Bod, for example, is popular with teenage boys.
How about a trendy backpack or messenger bag?
Board games are pretty safe. Lots of kids have never even played classic games, like Yahtzee or Sorry.
Gift certificates are great, but are more likely to go astray out of boxes. If you donate a gift certificate / gift card, I'd get it straight to the program organizers.
Nice journals paired with a fun pen...great gift for girls (and some boys).
I strongly suggest avoiding buying ANYTHING that requires owning some other item, unless it's in response to a specific request (for example, an Angel tree request). This includes video games (which require owning a particular game system), cell phone face plates, gift cards for downloading music, computer games, etc. Remember, people may not have a computer, etc. Depending on their financial situation, they may not have a television / dvd player, etc.
Edited to add: It is also important to consider the demographic of the teens likely to receive the gifts. Some items, such as things intended for use on/in the hair, can vary greatly based on the ethnicity/race/hair type of the person using them. I'd simply avoid products of this type, except for maybe colognes/perfumes, unless you receive a "needs/wants" list.