Dried apricots.
Dried apricots.
Durian (but only if you have a dedicated freezer).
Claire - thanks for the hint about the butter. That will come in handy!
Water. it is amazing. It goes hard and you can put it in drinks to cool them down
Peas
You can freeze a whole lemon and then grate it onto food... like into pancake batter or cake mix, or over fish to grill or anything you like. Tastes more lemony than just using the juice.