DH and I usually do traditional gifts (fruit/flowers this year), but he is so hard to buy for and I'm stumped this year!

I had thought about giving him a tree, but we just received a memorial tree and had a hard enough time figuring out where to put that one.

The modern alternative is appliance, but I feel like we already have too many of those.

What have you done for your fourth anniversary present (besides trees, edible arrangements, appliances)?