What to make of my unused GT-I5800 I've never rooted android before, as I considered it too risky for the device I'm actually using, but I just realized I have an older android phone (a GT-I5800) sitting around, so I thought I might as well make use of it. So I have been searching around for what I could do with it, but most questions ask this from the perspective of actually having a phone you use for calling people, so I thought it might help me, if I asked what people would recommend for me.

My perspective: I'm a PhD student in physics, I work on Ubuntu on my laptop, and various linux distros on large university clusters, I have a Galaxy Note 10.1 tab and a Galaxy S advance beside the above mentioned gt I5800, I can code in python and c++.

What I would be interested in (and anything else that might come to the mind of those more at home in the subject):


being able to access it through wireless to run stuff from my other android and laptop (ssh?)
having on OS on it, that does the bare minimum needed to access all the devices on the phone (turning them on or off too) and to run code (if possibly retaining the ability to use it as phone, i.e. dualboot, or some thing that has a minimum running mode and an "I'm a phone now" mode)
using it as a mini server
anything that seems like fun from a geeky point of view:)
a media server, using e.g. BubbleUPnP
a machine for development/coding, using e.g. Terminal IDE
a "picture frame" (before mentioned BubbleUPnP should be able to do that along, but many gallery apps in slideshow-mode as well)
a web server, e.g. with AndroPHP / Bit Web Server (PHP,MySQL,PMA) / Ulti Server: PHP, MySQL, PMA – also see: Turn a Android Phone with broken screen into dedicated Web server
have it ready as emergency/backup phome with some prepaid card
use it as "modem"/router for devices without a SIM card (tablets etc.) or without a data-plan, utilizing its hotspot functionality (sure you could use your main device for it; but using the old one keeps the juice in your main device ;)
use it as "test device" for any apps you want to try. With no important/daily-use/private data on it, you could even use some "risky sounding" apps here, and easily factory-reset it afterwards. For this, a separate Google Account might prove useful as well.