After Android 4.2 now its time for Android 5.0. Until now no has confirmed it from Google but today a Google employee, Manu Cornet, has somewhat confirmed the Key Lime Pie name by drawing a graphic that shows the evolution of Android.
As you can see the last Android mascot in the picture holds Key Lime Pie.
Despite this there’s no official confirmation regarding Android 50 Key Lime Pie. Its assumed that it will be launched in May 2013 Google IO.