This is the simple prompt that msfconsole gives you by default:
The second part, "exploit(psexec)" shows your current context is the exploit module named psexec. You can't change that because it's an important indicator of where you are. The first part, though, is just a default string to tell you you're in msfconsole. It can be controlled with the global Prompt option; you can set it to whatever you want:
setg Prompt lolhax
But that's not too exciting. To make it more interesting, there are several substitutions you can do to get more information out of the framework every time you hit enter. Check out this post from when the feature was introduced for more details on the existing variables.
Metasploit uses "workspaces" as a means of separating data ( and has for a long time). Now you can add your workspace to your prompt with the %W specifier:
Further, the save command now captures the current workspace as well, so the next time you fire up msfconsole, you'll start in the workspace you left off in and it will be displayed in your shiny new prompt.