Close Quarters

 You can arrange up to five quarters in a way that each quarter touches every other quarter. Starting with one horizontal quarter as the base, arrange two additional quarters to form a small "tent" over the first, resting lightly on top of it. The tricky part is adding two more. These two must touch each other at the tip, with their bases just barely filling the gap left by the previous two. The image to the right illustrates the structure.

You would think that this would make for an excellent bar bet, but before you challenge someone with this, try it yourself. It's a lot harder than it appears- you may need additional objects to keep the quarters from sliding about as you try to arrange them.