IIRC, Litecoin seemed like significant work, but after that, you could create a Scrypt altcoin by copying a source tree and doing not much more than changing the name (and pre-mining, because that's probably the point).
If I recall a bitcoin core dev back in the day made a website where you could just change a few variables: name, block time, block size, block reward, etc. And it would spit out your customized fork of bitcoin core. This is basically how easy it is to make an erc20 token these days.
