I would like to learn macrame. Only 4 knots so it seems like it should be really easy, once you get used to tying the knots reliably. I already know how to tie square knots, larksheads, and overhand knots. I forget what the 4th one is. Maybe its the inverse of the larkshead.
Problem is finding good projects to work on. I want a hammock, not a purse or a "wall hanging" (for those who don't know: it was invented by sailors, who used to do decorative knotwork off-hours and then sell them when they got onshore, but was taken up first by Victorian English ladies as a hobby, and then later by hippy-chicks in the 1960s). I am pretty sure that I could do a net bag, which is another thing I want (and plenty of them) as the city of Seattle keeps trying to pass a grocery-bag tax (20 cents per bag). Real netting (like a fisherman's net) requires a shuttlecock to wind the thread around, and a frame to keep the work taut, but you can fake it using square or overhand knots using many strands instead of just one (real netting is just one long strand).
I would also like to practice flat braids and sennets. Flat braids are handy for making belts. You can weave the soles of sandals, or make a braided carpet, using something like a sennet. Old pioneer gals used to take scraps of leftover fabric, roll them up, weave them into a braid, and sew the braid into a spiral, to make an old-fashioned braided rug.
A bolo tie is just a sennet. Not sure how to make the clip but it couldn't be too hard.
Beeherder, rectangles like granny squares are really easy. That's why Afghan blankets are popular.