In the wide world of Cydia, we often see kooky and crazy additions to the repo’s which don’t particularly have much function. AppActivationAudio is most certainly one of these, it gives the option to play one of 20+ sound effects every time you launch an application. Whilst funny in theory, it tends to get a little bit annoying and the only useful feature (apart from the fart sound) was that it allows vibration instead of sounds. This could prove useful if you had a faulty lock button and wanted to be notified when an application was opened, or any problem akin to this.
I just don’t see that this tweak is particularly useful, but you may enjoy it for a laugh. At $1.99 in my eyes, this is a definite time to save your money.