I know it isn't motocross, but most people love all types of two wheeled action and there are not many series bigger than MotoGP. Here is the 2025 calendar.

Provisional 2025 FIM MotoGP™ World Championship calendar

1 02 March Thailand Chang International Circuit

2 16 March Argentina Termas de Río Hondo

3 30 March Americas Circuit of the Americas

4 13 April Qatar Lusail International Circuit

5 27 April Spain Circuito de Jerez-Ángel Nieto

6 11 May France Le Mans

7 25 May Great Britain Silverstone Circuit

8 08 June Aragon MotorLand Aragón

9 22 June Italy Autodromo Internazionale del Mugello

10 29 June Netherlands TT Circuit Assen

11 13 July Germany Sachsenring

12 20 July Czech Republic* Automotodrom Brno

13 17 August Austria Red Bull Ring-Spielberg

14 24 August Hungary** Balaton Park Circuit

15 07 September Catalunya Barcelona-Catalunya

16 14 September San Marino Misano

17 28 September Japan Mobility Resort Motegi

18 05 October Indonesia Pertamina Mandalika

19 19 October Australia Phillip Island Grand Prix Circuit

20 26 October Malaysia Petronas Sepang

21 09 November Portugal* Algarve

22 16 November Comunitat Valenciana Circuit