Here are two of my favorite food DIY's:
JAM
Perfect gifts at weddings. Look how this bride, her grandmother and mom made just under 200 jars of jam for their guests. Named it after the farm which they got married. Also instead of gifts you could actually use them for the bread at the table.
COOKIESCookie buffet? Cookie Favor? Love this. Everyone can make a cookie. Great way to have kids help in preparation of a wedding or birthday party. Below is a cookie buffet with cute glass jars and then paper or glassine-lined bags. Use stickers or japanese masking tape so guest can take them to go. Great idea.

CANDY AND OTHER TREATS
I wrote about lollipops and candy bars as one of my first posts. I still think that nothing beats candy. It's easy, it's fast and always pretty in some smart packaged bag or box.
What are your favorite DIY food favors?