Unity - the Canonical-supported desktop environment that brought Ubuntu to the limelight in the general public.
It was sexy, easy to use, and had all the benefits of flashy proprietary operating systems, but it came equipped with the freedom of the free software world and the dream of convergence -- the ability to use the same OS on multiple devices. It was a dream come true. Then, in the Spring of 2017, Canonical dropped the bomb that they would cease (for business reasons) their support, and for most of 2017, Unity fans began to move to other Ubuntu variants to have a more certain support future. But their hearts remained with Unity. Then, in a sudden surprise side-attack, the UBports community appeared with the announcement of an installable version of Unity ("Unity8"), complete with 18.04 Bionic Beaver support (and of course 16.04 support)!
*EDIT MARCH 7, 2018: Unfortunately, as a result of the information in this link, Unity8 will not work in 18.04 for the foreseeable future. Our apologies and stay tuned while development continues.
What works and what doesn't
While you may be just as eager to install Unity8, keep the following in mind:
Overall, Unity8 is nice and buttery smooth. Sleek looks and sharp design is all on the table. These, however are not (yet) working: