Google's latest generation of nexus devices would be getting the Lollipop treatment from today. The Android 5.0 has been announced to be coming to the Nexus 4, Nexus 5, Nexus 7 and Nexus 10. This update follows shortly after non-Nexus smartphones like Moto G (2014) and LG G3.
If you're a proud owner of any of these devices, it should be arriving soon via OTA (Over The Air) update. Alternatively, if you're itching to update the newest firmware then you can flash it manually with with the official images which are available at Google's developer website. Be forewarned that this requires some technical knowledge and it is advised to backup all of your data before proceeding with the update.