Our tree has gone crazy with lemons. So, having juiced (and frozen) enough to last copious summer afternoons of gin and tonics and made a cake, I decided to make some iceblocks. Icing sugar, lemon juice and sparkling water. Easy! Next time I might try using honey, in place of the sugar, but we'll see.
1/3 cup juice
2/3 cup icing sugar
1 cup sparkling water
Makes enough for about 6 little iceblocks.