Introducing Aranya Prathet
The border town of Aranya Prathet (aka Aran) is known to Thais mostly for smuggling and gambling. (The casinos are over the border in Poipet.) For travellers, it's the busiest border crossing for trips to Angkor Wat and few actually stop here longer than needed to get their passport stamped. Though really, as border towns go, it's not that bad.
If you do spend a little time, Talat Rong Kluea is worth exploring. It's mainly thrift-store tat and cheap Chinese-made junk – for those seeking secondhand sunglasses and counterfeit Converse, it's the place to be – but the Rong Kluea experience isn't about what's being sold, it's about seeing the caravans of Cambodian traders pushing huge handcarts through a market so vast that many of the Thais coming here rent bikes (20B per day) and motorcycles (100B per three hours) to go shopping.