acm.sgu.ru was created ~16 years ago by programming contests participants from Saratov university: MikeMirzayanov and andrewlazarev. Today its codebase and infrastructure are completely outdated, and supporting it is unreasonably hard. Nonetheless, Codeforces team is regularly asked to revive acmsguru, since there is still a lot of interest in the problemset.
Here is the new functionality in Codeforces — additional section "acmsguru" in Problemset. All the problems from the old system are moved there. There are still a few things to do here: correctly port interactive problems, improve looks of statements, support the new section in Codeforces API, support adding these problems to mashups.
Anyway, you can solve the problems already, and view progress on separate standings page for acmsguru.
To save the spirit of acmsguru, viewing sources of other participants is disabled.
UPD: In some old problems checkers are compiled into 16-bit executables, so testing of these problems is temporarily not working.