We went to a common lunch at the institute, after which another 3 presentations followed. Robert Bradshaw on Cython, James Davenport on simplification in CAS and Dan Bernstein about elliptic curves. (Most people here are mathematicians, for example working on modular forms, cryptography etc.)
Then we had a conference dinner together, on which we discussed a lot of stuff - GPL2 vs GPL3 vs BSD pros and cons and problems and how to license SAGE and SymPy and whether "translating" something from C++ to Python is a derived work or not, I also asked William, the main author of SAGE sitting on my left hand side, how SAGE has started and about his future plans with it. Basically, we exchanged our experiences with working on an opensource project and how to motivate people to work on it, and how to do and especially not to do things. On my right hand side was Bill Allombert, one of the two authors of PARI/GP and also a Debian Developer, so we signed each other's gpg keys (that we use in Debian) earlier this afternoon. It's awesome, I am wearing my Debian t-shirt today, but I didn't expect to meet any Debian people here.
After a dinner we went to the math institute to have a coding sprint, some pictures using my cell phone from the sprint:
During the dinner and especially during the sprint I borrowed William's camera and recorded short interviews with conference participants. I am going to do more interviews tomorrow. I'll put the link to them later, when William puts them on the internet after the conference.