Celebrating completed work in a dev team

I'm wondering what you have done or seen in software development teams to celebrate completion of work?

Thinking about smaller scale (e.g. finishing a single story in a sprint) rather than larger (e.g. completing a project).

Could be anything from a gimicky USB gadget that the team programmed to hook into the work tracking system, team high five, a song, ringing a bell, something more formal, some form of gamification. Really anything that is a bit fun and can help build a sense of achievement and a culture of celebrating success in a team, and is a bit more engaging than a burn down chart.

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(Specifically not things that would encourage direct competition between team members, or cutting quality to get work out the door)