(First, much thanks to Mateo Geoly for posting these IPs on Facebook).
Apparently — although for how long this will last, I do not know — you can get around Egypt’s block of communications/social networking websites by using the numerical IP address as opposed to the name (which has to be resolved by a DNS). So:
To bypass government blocking of website names, use numerical IP addresses:
For Twitter “18.104.22.168”
For Facebook “22.214.171.124”
For Google “126.96.36.199”