I'm in Prague but not Czech. Tech scene here is strong. Good technical schools and almost all of the major players have offices here - Microsoft (Skype team), SAP, AWS, Google. A lot of startups too and a few game studios. If you're a Senior dev you can expect to make at most about 60-80k USD / year, more typically 50-60k. Managers can make more but no one makes Amazon USA type salaries here.
I work remote freelance for US companies and charge USD, so that could be an option too if you are coming from there. Not sure what you define as "interesting or cool" for work but I would imagine you can find it.