There are generally a lot of presentations/talks but I find that structure getting a bit stale and want to seek ideas that are outside just "giving talks" so that the devs can interact with each other.
Some requirements I've set for myself:
* a couple hours long (can be longer)
* able to be done within a small group (~3-5 people) of all skill ranges
* important that it's collaborative or interactive so that people aren't just working in silos
Some ideas:
* 1 day, very short hackathon-style activity
* work on something open source (probably need to decide on what package and set up instructions prior)
- https://en.wikipedia.org/wiki/Personal_software_process
- https://en.wikipedia.org/wiki/Team_software_process
2) Communication Techniques. Eg. 1) On Communication (2 vols) from HBR 10 must reads series 2) The Communication Book: 44 Ideas for Better Conversations Every Day by Krogerus and Tschappeler. While practicing always use problems of relevance and not hypothetical ones.
3) Decision Making techniques, in particular; Delphi Technique (https://www.toolshero.com/decision-making/delphi-technique/). Also see The Decision Book Fifty models for strategic thinking by Krogerus and Tschappeler. Again only use problems of relevance for practice.
4) Research Activities i.e. Problem Domain and Tech. Domain study. To identify new pain points, opportunities for Business and new Technologies/Languages/Tools for implementation. They need not be related but should always end with a PoC i.e. not just ending with a "talk". Inspiration: https://news.ycombinator.com/item?id=31626049
Many great and fun team / workplace activities. Applicable too more than just devs or work too!