Sorry for this, the site crashed on Friday and after investigation looks like was caused by the amount of traffic visiting the arcade. As a quick fix, I put some of the arcade traffic under "Under attack mode" on Cloudflare, and shut down the arcade for ~36 hours whilst I investigated.
I've made some changes now which should help (much more aggressive caching on expensive queries) which are now live and the arcade should be back to normal operation. This does seem to be an intermittent problem that keeps occurring so am keeping my eye on it.