As soon as testnet prove that everything working fine. Mainnet not sooner than two months I think. But you can play now with XEL, just download testnet client https://github.com/OrdinaryDude/elastic-reference-client watch this video for instructions how to run it https://player.vimeo.com/video/178616474?quality=1080p and paste your address here to receive some XEL for testing and fun.