Gaseous elements as solids

What do the gaseous elements on the right hand side of the periodic table look like when in a solid state? Do they form different crystal structures depending on how they are solidified? Has it ever been done (or is it predictable) for the lighter gases helium and hydrogen?

Helium can solidify, but only with high pressures and very very low temperatures.

The noble gases are held together only by Van der Waals forces, and when they’re in solid form the look like clear jelly, right down to the wiggling (I’ve seen some of these – a guy in a nearby lab was doing work on solid noble gases). They don’t have a huge amount of structural integrity.

[Homer] Mmmm… jelly [/Homer]