Prebuilt packages on Ubuntu 15.04 (vivid)

Prebuilt Packages are currently not supported for Ubuntu 15.04, but by following this tutorial, You can install Ubuntu 14.10's Packages on Ubuntu 15.04.

sudo apt-key adv --recv-keys --keyserver hkp://keyserver.ubuntu.com:80 0x5a16e7281be7a449
echo deb http://dl.hhvm.com/ubuntu utopic main | sudo tee /etc/apt/sources.list.d/hhvm.list
sudo apt-get update
cd /tmp  && wget http://security.ubuntu.com/ubuntu/pool/main/libm/libmemcached/libmemcached10_1.0.8-1ubuntu2_amd64.deb
sudo dpkg -i libmemcached10_1.0.8-1ubuntu2_amd64.deb && rm libmemcached10_1.0.8-1ubuntu2_amd64.deb
sudo apt-get install -y libgnutls26
wget http://mirrors.kernel.org/ubuntu/pool/main/r/rtmpdump/librtmp0_2.4+20121230.gitdf6c518-1_amd64.deb && sudo dpkg -i librtmp0_2.4+20121230.gitdf6c518-1_amd64.deb && rm librtmp0_2.4+20121230.gitdf6c518-1_amd64.deb
sudo apt-get install hhvm

# If you are getting segfaults
sudo apt-get install hhvm-dbg
# Living on the edge (rebuilt everyday, unstable)
sudo apt-get install hhvm-nightly
# Segfaults in the nightly
sudo apt-get install hhvm-nightly-dbg

If this repo is slow for you, choose a different Mirror.