update upcoming events

README.md

@@ -6,7 +6,8 @@
 - [Brain Data Modeling Hackashop: February 2024](linkml_neurodata_hackashop_2024/README.md) - at the  [International Computer Science Institute (ICSI)](https://www.icsi.berkeley.edu) in Berkeley, CA, USA, **February 5-7 2024**.
 - [Cosyne: February 2024](Cosyne_2024/README.md) - A tutorial session on NWB and DANDI will be held during the
   Computational and Systems Neuroscience (COSYNE) 2024 conference in Lisbon, Portugal on **February 29, 2024**.
-- [NWB Developer Hackathon: April 2024](HCK18_2024_Dev_Hackathon_DataJoint/README.md): **April 17 - 19, 2023** at DataJoint Headquarters in Houston, TX, USA
+- [NWB Developer Hackathon: April 2024](HCK18_2024_Dev_Hackathon_DataJoint/README.md): **April 17 - 19, 2024** at DataJoint Headquarters in Houston, TX, USA
+- [Open Neurodata Showcase: Virtual, June 26, 2024](HCK19_2024_OpenNeurodataShowcase/README.md): **June 26, 2024** (virtual) 
 - [NeuroDataReHack: July 2024](HCK19_2024_Janelia_NDRH/README.md) - NeuroDataReHack 3 will be held at HHMI Janelia Research Campus in Ashburn, Virginia, USA **July 8-12, 2024**.