Well, fresh lemon balm makes amazing tea. I was introduced to it by my host-mother when I was an exchange student in Scandinavia. It's yummy, and herbalists credit it with lifting winter blues.
The problem is it doesn't grow in the winter - hence the ice cubes.
This technique is also great for preserving things like fresh basil. To keep them green, blanch briefly in hot water (otherwise they turn black in the freezer) chop into small bits, pour water over the top, and freeze. This also works great for basil.
Pop out of the tin, store in a bag, and just add to boiling water when you're ready to brew.
Do you have any tips for preserving your summer bounty?