Hi Guys,
Yes, I'm still alive....just got busy with lots of other life things. 
So, I am working on a non-puppet project, but as a puppet builder, I am using puppet building supplies.  lol
Building a creative environment for our Children's Department at church.  One room is going to look like you
are inside the whale's belly from the story of Jonah.
Soooo, the walls are painted, now here comes the challenge. I need to make the ribs and backbone of the whale
that will be across the ceiling and down the walls.
I am using 1" foam and making it into cylinders.  But I can't remember what to use to paint it.
Isn't there something I can put as a base, before spray painting it, since spray paint doesn't work so well
on poly foam.
Any suggestions?  \
Thanks!
Sara

You can use floral paint to paint foam (Design Master Colortool Floral). You could also use RIT dye. Both can be used to color your foam, but still keep the flexibility to the foam.

Since you're using what sounds like large amounts of foam, and its in a hospital with people touching it, I would try the rit dye. The dye will soak into the foam and color it throughout.

I agree with the RIT dye suggestion.

I think the RIT dye suggestion is a good one, but although you have said that poly foam doesn't work well with spray paint, I think it depends on how you are using it as I have used acrylic spray paint on poly foam and never had a problem with it still being as soft and flexible as raw foam, I just make sure that I give very thin layers and maybe only 2-3 light layers, it covers the foam in the colour, but doesn't effect the softness of the foam. I also second the floral spray paint, it works really well and comes in lots of different colours!
also, I don't remember anyone saying it was for a hospital! I think lovable puppet pals said it was for a children's play room in his church! lol! but the same applies I guess, people are going to want to touch it, so it will have to be pretty hardy to stand up to children!!
there is another way, but its a little more involved, but will help to protect the foam and give it a more smooth finish, you could try the cheap silicone skin technique that pagestep007 posted up a while back, it uses readily available bathroom sealant silicone mixed with a little vinyl paint for colour, you simply squirt a bit of the silicone from the tube, mix a bit of whatever colour you want into it and then paste it onto the foam with a pallet knife, lollipop stick or whatever you have, and leave it to dry, then give it another coat, leave that to dry too and you should have a really nice, smooth coat to the foam that will not only stand up to a bit of roughness from the kids, but also will look more like the whales rib cage bones, and is a little tactile too which is never a bad thing in a kids play room! I have tried this technique and it works really well and the silicone skin on the foam lasts a really long time and takes colour really well!