My mobile phone has a Star Trek 'red alert/yellow alert' app which reminds me when signal is lost, someone texts etc. Goes to blue alert on charging. I have had a few comments.
I also have a lockscreen Star Trek theme which displays the LCARS interace and a Trek style time, date and power display.
I colelct t-shirts and I of course have numerous Trek ones I wear. My 'Resistance is Futile', black t-shirt with the Borg logo is a particular favourite.
On a related note, I get very fed up with 'geeks' who feel ashamed or nervous about wearing t-shirts of their fandom in public. Seriously. Sports fans stroll around with their team shirt on, people wear tapout t-shirts.
For example, I am a pro-wrestling fan, as I type this I am wearing an AJ Styles t-shirt. I know many wrasslin' fans who are terrified of wearing a t-shirt in public. I always tell them to get a grip and get over it.