From Team Fortress Wiki
Birthday mode, also sometimes called party mode, is a server mode that enables various "silly gibs" to be used alongside the normal gibs. It is automatically activated on August 24, the release date of the original Team Fortress in 1996. It can manually be enabled on servers by using the setting
tf_birthday 1 in the server.cfg file.
Many of the gibs seen in this mode are used in the low-violence version of the game as full-time replacements. A beach ball appears in BLU's spawn room at the beginning of the round and may be propelled by most attacks and the Pyro's compression blast. Health kits are replaced with birthday cakes and ammo packs are wrapped with a bow in a style similar to a present.
Prior to the August 23, 2011 Patch, birthday mode would automatically draw a Party Hat on top of the classes' heads. This has been moved to its own item that can be chosen like other hats. This prevents a number of clipping issues the Party Hat had with non-default hats.
During that time, birthday mode completely disabled the use of violent gibs, and blood was replaced by balloon particles. Some violent gibs are now spawned along with presents and other silly gibs.
Birthday mode uses both the normal gibs and silly gibs that low-violence versions of Team Fortress 2 use.
- Fixed bug with holiday date computation that turned on Birthday mode a few days too soon.
- [Undocumented] Added a "Happy Birthday Team Fortress" beach ball that will randomly appear in BLU's spawn at the start of a round when Birthday mode is enabled.
- Added TF birthday replacement models for health kits and ammo packs.
- Added TF birthday Party Hat and Noise Maker.
- [Undocumented] Updated the TF birthday ball to read "Happy 15th Birthday".
- [Undocumented] The original birthday mode party hats are no longer used.
- [Undocumented] Normal gibs are now enabled along with silly gibs in birthday mode.
- [Undocumented] Balloon particles no longer replace blood in birthday mode.
- [Undocumented] Cheering sound effects no longer occur automatically in birthday mode; this has been moved to the TF Birthday Noise Maker.
- [Undocumented] Birthday mode is now enabled. Upon log in, users will receive a Birthday Noise Maker and a Party Hat, if they don't have one already.
- It is possible to kill another player by propelling the beach ball towards someone at a fast enough rate, regardless of whether the player is on your team or not. When the player is killed through this method, it will appear as if that player committed suicide.
- The Short Circuit can destroy the beach ball. It is unconfirmed whether this is intentional.