The term cloud is just a new marketing term for a good old fashioned web server. Update: it has now matured to be more than that: https://en.wikipedia.org/wiki/Cloud_computing. In any event, there are quite a few things you can do with a web server at home or even in a small business. Everything can be accessed from any computer on the network. As long as the client computer has a web browser such as firefox or etc. I predict the web server will be the next home appliance. If you want to program your own web site, w3schools.com and http://www.htmlcodetutorial.com/ are a good place to start learning about web development. www.howtoforge.com has some excellent tutorials on setting up web servers.
Also consider reading:
If you want to install existing web applications, here is an introduction: https://www.instructables.com/id/Introduction-to-installing-web-apps/
The new arm based devies such as the Cisco Linksys Nslu2, Raspberry Pi, Beagleboard, and a host of other arm based systems can al be light weight web servers.
All the screen shots are taken from an old Dell GX1 (Pentium II) which is considered outdated technology by today's standards but still works for us. This particular system is running Ubuntu 12.04 lts that was originally running 6.x that we have upgraded over several years. All the upgrades were done without having to redo the computer. We do back up the system at intervals with Clonezilla. Update: system has been upgraded to a PIII via a cpu swapout.
processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 5 model name : Pentium II (Deschutes) stepping : 2 cpu MHz : 448.648
Update: I just upgraded that old machine to Ubuntu 12.04 LTS in place (ie no reformatting or complete reloading of the os). I did have to redo the mail server set up though and update some of the web applications. Most of which I would have had to do anyway.