I made a bee hotel for the garden. It can be made with any wood you've got laying around, and it's fairly forgiving of any minor making issues. It does come out pretty big, so unless you're really looking to make something big, then scale the widths of the pieces (perhaps by half for a more reasonable build).

Making hexagons isn't especially easy, but this design keeps the number of mitre cuts to a minimum and makes physically joining the pieces together relatively easy. Making the angled cuts needs a decent chop saw, but thankfully all the angles are the same so just one angle-setting for all the cuts. The pieces can be screwed together fairly easily, although pre-drilling requires drilling into the corners at an angle.

Bee hotels need to be somewhat protected from the rain. This design has 'overhanging' tops, which shield from the rain but don't make shadows from the sunshine. In practice, the rain run-off seems to follow the wood, although wind-blown rain does whatever it wants. The design needs a back on it if it's not against a solid wall or something. It's got a 200mm depth, which apparently is the 'best' depth. Making some dividers or shelves is pretty easy, and means you can fill each section with something other than hundreds of bits of bamboo.