When work on a project stalls or becomes undesirable, and colleagues are faltering, rise to the occasion and lead the way, even if you're not a manager.
In leading by example, you're showcasing that not only do not care about advancing into the unknown, but that the end justifies the mean. By actively doing the tougher stuff, which may not even be your responsibility, the team will be motivated to continue. Your standing among colleagues will also improve which can benefit you in the future when it may be even harder.
Don't be afraid to step out from under your defined role and meet the challenge when others have backed off or delayed. We all make mistakes, coming out of the comfort zone to speak up or work further than you need to will teach you more and improve character.