I always say yes when the boss is handing out free training. It may not be immediately applicable but learning new things is always a good thing. Keeps the learning mechanism tuned up. Always a good thing in our line of work. And who knows? You may like it a lot. At worst you'll be ready to raise your hand when they need someone with C# experience for 'a short job.' More education = more value to your employer.
Sigerson
"No pressure, no diamonds." - Thomas Carlyle