I use a mixture of systemd-nspawn and different user logins. This is sufficient for experimentation, for actual use I try to package (makepkg) those tools to have them organized by my package manager.
Also LVM thinpools with snapshots are a great tool. You can mount a dedicated LV to each single user home to keep everything separated.
In case you get stuck again and need more games:
Notable mentions: WorldOfGoo, Human Resource Machine