The Windows Phone Store is has plenty lockscreen apps that allows you to add a certain level of customization to your Windows Phone lockscreen. LockAgenda hopes to attract your attention by displaying more of your daily schedule of appointments on your lockscreen.
The app has several display options for your appointments and a decent selection of lockscreen wallpaper images to choose from as well. You can even use your own image as your lockscreen wallpaper. I can see some appeal with LockAgenda and if you need to see more of your calendar from your lockscreen it may be an option worth trying.