.NET developers have probably heard about LINQPad, a handy "programmer's playground" where you can type C#, F# and Visual Basic .NET code into a scratchpad and quickly debug it. This can be a better alternative to, say, constant recompiling when tweaking logic.
Unfortunately, LINQPad's more tempting features only come with the paid versions, but a free alternative in the form of RoslynPad has arrived.
Yes, LINQPad does have a free version and although it does a lot, it's missing some core features such as full auto-completion and integrated debugger. RoslynPad doesn't have a debugger either (well, not yet anyway), but it makes up for it by being open-source.
Development is ongoing, so it's possible RoslynPad will come with all of the paid LINQPad goodies, minus the price tag. If you're a die-hard LINQPad user, give it a go and see if it's the substitute for you.
RoslynPad [Official site]