I have been asked to speak offsite (not at my home church) a few times this past year, which is a great thrill. Interestingly it has been pretty much a split between speaking specifically on worship, and speaking on any other biblical theme.
Tonight I am speaking on worship (link for when and where). The thing that never ceases to amaze me is how I can never seem to force myself to speak the same talk twice. I attribute that to continued learning for sure. Usually there is enough of a break between engagements that I have learned more, thought of better ways to express the same thought etc. Although much of the material builds on previous thoughts and talks I am excited about the opportunity to explore again with new fresh thoughts (at least to me) the musical side of worship and its implications for the Christian community today.