Over the years, many a jailbreak tweak has taken advantage of the heads up display that appears when you press one of your iPhone's volume keys; for instance, biteSMS allows you to invoke quick compose for SMS messages by simply tapping the HUD when it appears.
While most tweaks that use the HUD only utilize it for some auxiliary function, HUD Controls Plus focuses solely on the HUD.
With that in mind, it's appropriate to refer to HUD Controls Plus as a supercharger for your iPhone's heads up display...