Often done in college and upon first entering the "real world". Where a person with little means ends up using plastic milk crates as bookshelves and can build anything with concrete blocks, boards and enough duct tape.
My first time living out of college dorms, I had an apartment with one of those round tables with one leg right in the middle, making it very unstable. It didn't help that the floors in this apartment were already a little crooked, so things would often slide and/or roll off of this table. So over Christmas vacation that year, I decided to take some of dad's spare wood and build a solid table. Just a couple of two-by-fours, nails and screws, and I'm not sure what type of planks for the table-top. I wanted to paint it a nice deep burgundy to match the couches, but it ended up neon- bright pink. Needless to say, we always used a table cloth.
The year after that our apartment had a solid table, but I needed a bookshelf. I took the planks off the table-top and nailed them together in shelf formation. The boards were a little too narrow, and not having any sort of bracing it was a very wobbly bookshelf. However, it lasted the year, and now some of the two-by-fours that made the base of the table are part of the bunny hutch I built this weekend.