Archive October 2026 meetup and set up November 18th event and announcement

challenges/archive/readme.md

@@ -19,6 +19,7 @@ This folder houses the historical archive of all past monthly 3D printing challe
 
 | Month | Challenge Title | Theme / Focus | File |
 | :--- | :--- | :--- | :--- |
+| **October 2026** | **Halloween Prints** | Costume props, spooky decor, and specialty filaments | [October-2026.md](October-2026.md) |
 | **September 2026** | **Practi"FALL" Prints** | Functional utility and everyday practicality | [September-2026.md](September-2026.md) |
 | **August 2026** | **Gridfinity Extravaganza** | Modular storage systems and custom bin designs | [August-2026.md](August-2026.md) |
 | **July 2026** | **Scarf Seams** | Seamless z-seam placement on curved spheres | [July-2026.md](July-2026.md) |
@@ -36,3 +37,7 @@ This folder houses the historical archive of all past monthly 3D printing challe
 | **December 2025** | **Bring Your Test Models** | Calibration prints, torture tests, and holiday ornaments | [December-2025.md](December-2025.md) |
 | **November 2025** | **Wait, This Was Printed?** | Flawless layer-line-free surface finish (25mm cube) | [November-2025.md](November-2025.md) |
 | **October 2025** | **Is it Glass or Clearly Natural?** | Optical clarity challenge using 3D Fuel Clearly Natural | [October-2025.md](October-2025.md) |
+
+---
+
+**Last Updated**: October 30, 2026