How can I acquire REP on a testnet like Rinkeby or Kovan? There are some old threads in here with some outdated links (mainly to dev.augur.net) which no longer work. Other links I've found in Reddit, etc also don't work.
dev.augur.net occasionally goes down for maintenance but it is still the officially supported testnet front end and where you can acquire Rinkeby testnet REP.
Specifically in the UI you can go the the "Account" section and then the "REP faucet" page to give yourself test REP.