Last night, following my game of 7-Wonders (solo) and building my civilization, I had time before bed to break out, Spyrium for some solo play. Plus my tea wasn't gone. ;)
Since purchasing the game from GeekMarket, I experimented with one of the only solo variant's out there for the game that I came across on, you guess it, BGG. This variant is actually modified from "Simple solo variant" by another BGG member. Spyrium is a unique worker placement game, and really the interaction and choices of your opponents is part of what makes it fun (and challenging). This solo variant does the best it can to at least make you think.