I always joke that I can geek out on just about anything, given the right incentive:
There was the year I started experimenting with different flours (oh, the variety we had!), and the time I took up handspinning (so much fibre!), and those years when I was a kid when I was so into miniatures (I learned about the importance of scale, and took a night course in drafting at the local college with my Dad). When my oldest son was born, my husband and I ran a website on natural parenting for several years before life got busy and I lost interest (but not before I geeked out on pregnancy tests and peed on just about every stick on the Canadian market, putting them all into a convenient HTML table for easy access). Obsessively geeking out is something on which I thrive when a topic catches my interest.