SHACAL
Block ciphers built from the compression functions of SHA-1 and SHA-256, an unusual way to recycle a hash.
SHACAL-1 was designed in 2000 by Helena Handschuh and David Naccache. It takes the SHA-1 compression function and turns it into a block cipher with 160-bit blocks and keys up to 512 bits. SHACAL-2, based on SHA-256, was among the ciphers recommended by the NESSIE project.
The odd part is that SHA-1's collision weakness does not carry over to the cipher. A hash that has been broken can still work as a cipher.