The event started earlier today and is expected to wrap up on Saturday, July 28. Now here is where things get interesting. ESA has not one but two streams going for this marathon. The first stream (primary stream?) is a continuous marathon and will go nearly non-stop from now until the 28th. The second stream kicks off on July 22 and is not continuous but will instead go offline each night. Both streams contain different games being run! That's why you should take a look at the complete schedule to see when and where the games are that you want to watch, because they might not all be on one stream.
All donations go to help out the Save the Children charity. You can select which specific stream you want to donate towards. There are a number of donation incentives that are going on for both ESA Summer streams this year. You can donate through the ESA Event List page.