Here are just a few neat ideas for Tu Bshvat mostly for the younger set:
Matzo Ball soup has an activity book for Tu Bshvat which is great for readers but also can be used for younger children with adaptation.
Jennifer from RonyPony.blogspot.com as a nice Tu BShvat activity pack (things like patterning, matching fruit to trees, senses etc.) with the added plus in that the worksheets have Hebrew and English terms. Log into your google account before trying to download.
Fall tree dice game
Log art project shared via The Crafty Crow
Tree trunk rubbing
Life cycle of an apple tree with printables
Tutorial on how to paint a spring tree which would work very nicely as an Almond tree
Chocolate tree tutorial
You may also be interested in the following post with Tu Bshvat crafts: Flower ideas
One more thing- I did a simple project with my daughter related to orlah and neta revai (since I figured thats really a major part of the whole concept of Tu Bshvat.) Basically I asked her to draw me a picture of four trees of different sizes and we labled them 1-4. Then we discussed how a tree grows every year. I asked her for each year “Do we eat the fruit this year?” and then we talked about bringing the fruit to Jerusalem in the fourth year.