X-Men/Captain Universe was a special $14.99 mail order one-shot that allowed YOU to become Captain Universe by filling the required fields (Name, Gender, etc.) and sending both the order form and cash to Marvel. Though it was a one-shot issue there were two versions of the comic (and the extras that came with it) so that both Men and Women could order the set and star as Captain Universe in their very own X-Men comic. In order to make the events that occured within the issue part of mainstream continuity Marvel retconned the comic to make it so that Jeff Christiansen, who is known best for his work on titles such as Official Handbook of the Marvel Universe, was the official Uni-Power host featured in the issue.
The comic also came with a poster of Captain Universe and The X-Men signed by Tim and Greg Hildebrandt as well as a unique Captain Universe card with your name and stats.