Clock and Calendar
To enable the new clock and the new calendar-app open regedit and navigate to the following key:
Once you have arrived - create a new key with rightclick, "new" and create a new DWORD 32 bit value and name it "UseWin32TrayClockExperience" and the new clock app will be enabled in the task bar.
New lock-screenYou can also enable the new lock-screen with a registry tweak.
Now execute a double-click on "Threshold" and change the value to 1 (instead of 0).
Once you lock the pc or log out you will ne able to experience the new lock-screen.