I had limited success myself. I was able to hype a few persons about Scala. But in fact none of them made a meaningful effort to try to switch (usually from Java).
I would like to read both success and failure stories here. Both long tries and short ones.
My goal is to find ways of presenting Scala to another person, friend, co-worker (not an audience) that will make them want to use this great language.
I recommend posting pictures of the Programming Scala book on the wall and constantly suggesting that "Scala can do that" whenever a programming question comes up. It convinced me to look into Scala, but I can't say that I've "switched".
I can tell you how I found Scala, which may help.
Two guys at my work had mentioned it once or twice, and maybe I'd seen a few of those "Is Scala the next Java?" posts on blogs, but neither of these had convinced me to look into it. Then I noticed that my local Java User Group was having a talk about Scala, and I thought, "That's what I need: someone to explain it to me in less than two hours using PowerPoint, while I drink free beer." Ironically, not wanting to be totally bamboozled by the talk, I spent a couple of hours before the talk reading about Scala and looking at a few simple examples.
After seeing someone get excited about little snippets of Scala code who I didn't know, but who was clearly a pragmatic, non-academic programmer, and who was obviously trusted enough by other people to give a talk, I decided I needed to write a few little programs to check it out myself and haven't looked back. Now I run a multi-million dollar company where I write a whole Scala application from scratch each day and sell each one for US$70,000. (Okay, the last bit isn't true - yet.)
To summarise, the following helped get me across the line, and may help get your friends and workmates across the line:
Two resources I found very useful in learning a little about Scala as a complete newbie and which you could easily pass on to your targets:
I've also written a blog entry about "Why your company should let you use Scala at work" which is targeted at people like those you are trying to reach (and their managers - and my managers!).
I've been sold after hearing an excellent Scala presentation by Mr. Odersky himself, at Jazoon'2008 in Zurich. The main selling points were:
You see — I wasn't a functional programming aficionado; only after one year I became interested in FP.
I would liken leaving Java behind to giving up heroin. It can be explained the various merits of alternatives, such as beer or chocolate and also the various drawbacks of continued use: like destitution, prostitution or death.
But generally, giving up heroin is something that people usually do when they are good and ready
I think it will be hard to make the case, at least to me, until a better IDE is built. I would agree that scala is much much better than java as a pure language. But in terms of overall developer productivity, I would wait until we see a better tool, The guys building the eclipse plugin have done an admirable job but the task at hand is very large. While, for example, I dont think we need all the refactorings that eclipse provides, we need at least some of them. There are some other issues as well. We have +1M LOC and the eclipse projects are quite big. The scala plugin really slows down the dev env because of the weaving the scala plugin needs. It may be the case that some project can work around this stuff but I dont think we can. Sadly, by the time the dev envs are really ready, java may have closed the gap enough to make it tolerable.