Scouts are given a list of map symbols to draw from memory.
Paper, pencils/pens, list of map symbols and descriptions.
Divide the Troop/Pack/Unit into groups of 4-6 and issue each group with a piece of paper and a pencil. The Leader reads out a map symbol and the groups then have to try to draw that map symbol from memory. Swap sheets between teams and mark. Prizes for the team who gets the most correct answers.
If you want to make it really difficult you could include symbols from different map scales (1:25,000, 1:50,000 etc.) or even different publications, such as Harvey maps.