Jelly Bean Launcher makes your home screen look and feel like you have Android 4.1 instead of an older version. There are a few weird issues with the execution, but Jelly Bean Launcher is a nice compromise if you don't want to root.
You can make this launcher your full-time home screen by making it the default app. The launcher grabs a few widgets from your current app's menu to paste on your home screen. It doesn't check your current home screen layout, though, so you'll be stuck rearranging things to make them match. Since your smartphone or tablet won't have Jelly Bean's secret Project Butter, it won't be as smooth as real Jelly Bean. It does seem to make scrolling through menus noticeably faster, though. When you first use it, Jelly Bean Launcher runs you through Android's first-time tutorial, which is bizarre. If you're using a launcher, you probably know what you're doing.
It's not as good as Jelly Bean, itself, but it's the next best thing for sure. Jelly Bean Launcher gives you a taste of the sweetness that is Android 4.1 and 4.2. If you want more than that, you're going to have to root your gadget or purchase an upgrade. Try this out if you're tired of playing the waiting game when it comes to Android.