Add pyhep 2025 events.

Author: riga

_activities/pyhep.md

@@ -53,6 +53,8 @@ with the aim to provide an environment to discuss and promote the usage of Pytho
 {:.table .table-hover .table-condensed .table-striped}
 | *Workshop*     | *Location*             | *Date*                | *Agenda link*                                                                         |
 | -------------- | ---------------------- | ----------------------| ------------------------------------------------------------------------------------- |
+| PyHEP 2025     | Online workshop        | October 27-30, 2025   | tba                                                                                   |
+| PyHEP 2025.dev | Seattle, WA, USA       | July 14-17, 2025      | [Indico](https://indico.cern.ch/event/1515852){:target="_pyhep2025_dev_indico"}       |
 | PyHEP 2024.dev | Aachen, Germany        | August 26-30, 2024    | [Indico](https://indico.cern.ch/e/PyHEP2024.dev){:target="_pyhep2024_dev_indico"}     |
 | PyHEP 2024     | Online workshop        | July 1-4, 2024        | [Indico](https://indico.cern.ch/e/PyHEP2024){:target="_pyhep2024_indico"}             |
 | PyHEP 2023     | Online workshop        | October 9-12, 2023    | [Indico](https://indico.cern.ch/e/PyHEP2023){:target="_pyhep2023_indico"}             |
@@ -65,6 +67,35 @@ with the aim to provide an environment to discuss and promote the usage of Pytho
 
 The advert and details on these workshops are given below.
 
+## PyHEP 2025 & PyHEP.dev 2025
+
+As in previous years, two events will be held again this year:
+
+PyHEP 2025, on October 27-30, is a continuation of the free, online workshop series, which has been bringing
+Python HEP developers and physicists together these past years.
+
+PyHEP.dev 2026 is intended for Python HEP software developers to plan a coherent roadmap and make priorities for the upcoming year. It will be held in-person in Seattle, WA (US) on July 14-17.
+It will include presentations by participants, but the focus will be on birds-of-a-feather style group discussions.
+Attendance is limited to ~50 participants.
+
+### Organising Committee
+
+Matthew Feickert - University of Wisconsin-Madison<br />
+Nikolai Krug - LMU Munich<br />
+Peter Fackeldey - Princeton University<br />
+Ianna Osborne - Princeton University<br />
+Marcel Rieger - Hamburg University<br />
+
+<b>Local organisers:</b><br>
+Gordon Watts - University of Washington
+
+### Sponsors
+
+One of the, or both, events, is/are kindly sponsored by (details on the Indico pages)
+
+![IRIS-HEP]({{ site.baseurl }}/images/pyhep/IRIS-HEP_logo.png){:height="60px"}
+![NSF]({{ site.baseurl }}/images/pyhep/NSF_logo.jpg){:height="60px"}
+
 ## PyHEP 2024 & PyHEP.dev 2024
 
 Two events will again be held this year: