Questionable Registrations

I am starting to notice some strange/questionable registrations coming into my website at http://www.sportszonetemplates.com

For example:
User Name: 0x0f0d3
E-mail address: aniol2xx@o2.pl

User Name: 9ji7g4x
E-mail: ucja124@o2.pl

There are a couple more but this should give an idea of what’s happening.

I was wondering if anyone had a comment or suggestion about these. Could they be hack attempts or something else, and should I take some kind of precautions.

Any feedback is appreciated.