I briefly mentioned in the previous locus post that a treasure map is a fun application of the concepts in locus. Think about pirate movies..."5 paces from the tree, and 3 paces from the fence!" (There could be up to four possible locations for that treasure...)
I first tried to design a treasure hunt using the whole school, a la geocaching, but the impracticality of that became quickly apparent. So, I designed a smaller scale treasure hunt within my classroom.
It's designed for use with student desks in a 6 x 5 grid. Before class, you hide treasures (I used colored index cards with a funny quote or comic) by taping them under certain desks. You provide the students with a map of the desks they can write on, and a sheet of compound locus descriptions that tell them how to locate the treasure.
I've used this several times and it was successful and fun. I hope you find it useful!