Microsoft
Brad Silverberg, who led the team that made Windows 95, and is now an investor with Ignition Partners, a VC firm he founded.
The $4 is sponsored by Microsoft, along with some of its top executives and most prominent alumni:
Current Windows Phone boss Joe Belfiore is listed as a sponsor, as are ex-execs like John Ludwig, Brad Chase, and David D'Souza who were heavily involved in the Windows 95 launch.
(Even with those sponsors, it's not free: It's $47.50 to get in to the Team Reunion.)
When Windows 95 launched on August 24th, 1995, it was the biggest software release the world had ever seen. People waited in line overnight to get it, like they do with iPhones today. A worldwide marketing campaign was launched with roadside billboards across the globe; people threw Windows 95 release parties and barbecues (seriously); commercials featuring the Rolling Stones' "Start Me Up" were impossible to ignore.
Ex-Microsoft employee Julie Weed recalls a time when a coworker was in Chicago's O'Hare airport, ahead of the Windows 95 launch.
It somehow came out that he worked for Microsoft, and a crowd formed around him and forced him to show off an early version.
It was a $4. Weed actually wrote a book about it: "$4."
Windows 95 itself has, in a very large part, set the tone for the Microsoft since. $4and taskbar still with us in the Windows 10 release.
And it was the first version of the operating system to have any kind of understanding that there was this thing called the "Internet" that would go on to get kind of big.
Windows 95 was a highwater mark from Microsoft's golden age. It's no wonder Microsoft wants to celebrate it. The event page promises food, drinks, entertainment, special guests, and "surprises."
If you want a little Windows 95 release nostalgia, check out this interview with the team from around that time, as linked on the event's page: