Internet-scale distributed computing?

[Skip Montanaro]

Failing to find any obvious references with some googling, I turn to the
Python folks who have lots of information about lots of different
application domains.

I'm sure many of you are aware of SETI at Home, Folding at Home and Google
Compute, all tools to tackle certain large computational problems on an
Internet scale, typically by soaking up unused cycles on otherwise idle
computers.  A bit of googling didn't turn up any others, so I'm wondering:

    1. Are there other active projects similar to SETI at Home or Folding at Home?

    2. Are there tools available to make it easier to build such
       applications?

Thx,

Skip