I'm a member of the demogroup Poo-Brain and the first ever demoparty I went to was Revision 2011. Demoparties are computer arts festivals spread out over (mostly) Europe.

From Wikipedia:

The demoscene is an international computer art subculture that specializes in producing demos: small, self-contained computer programs that produce audio visual presentations. The main goal of a demo is to show off programming, artistic, and musical skills.
The demoscene's roots are in the home computer revolution of the late 1970s, and the subsequent advent of software cracking. Crackers illegally distributed video games, adding introductions of their own making ("cracktros"), and soon started competing for the best presentation. The making of intros and standalone demos eventually evolved into a new subculture, independent of the gaming and software file sharing scenes.

PB01: Party Gipfel

Our very first PC Demo entry! Heavily inspired by The Final Countdown and after years of just attending we finally decided to grow some balls and release this demo, Party Gipfel, at Revision 2013. We were overwhelmed by all the postive feedback we got from everybody and it pretty much went downhill from there. 

Party Gipfel placed 7th out of 18 entries at Revision 2013.

PBO2: Zuperstar

After binge watching Jesus Christ Superstar for weeks we finally decided to make a demo about it. If you're big into Jesus you might want to skip this one. 

Zuperstar placed 5th out of 8 entries at Evoke 2013.

PB00: FrikandelXXL

Born out of a freak obsession with frikandel and sheer Unity3D abuse, meet FrikandelXXL! This is also the first time we joined forces with the legendary Okkie.

FrikandelXXL placed 4th out of 8 entries at TRSAC 2013.

PB00: Paardicle

Probably my personal favorite. Produced at the party and after the deadline, this demo does not fuck around and is the first in our line of horse themed demos. 

Paardicle placed 1st out of 7 entries at Outline 2014.

PB05: Ziphorse

A 'remix' of the amazing Ziphead, winner of the PC Demo compo at Revision 2015. 

Ziphorse placed 1st out of 4 entries at Outline 2015.

PB06: Cubed Adventure

Poo-Brain's attempt at something with design and some thought behind it; Cubed Adventure! Based on concept art by Oni and with great music by RoccoW!

Cubed Adventure placed 4th out of 7 entries at Evoke 2015.

PB11: Staart Horse

Staart Horse placed 1st out of 3 entries at Outline 2016.